/*
 * Copyright 2003,2004 The Apache Software Foundation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package cn.taketoday.context.cglib.proxy;

import java.lang.reflect.Method;

/**
 * Map methods of subclasses generated by {@link Enhancer} to a particular
 * callback. The type of the callbacks chosen for each method affects the
 * bytecode generated for that method in the subclass, and cannot change for the
 * life of the class.
 * <p>
 * Note: {@link CallbackFilter} implementations are supposed to be lightweight
 * as cglib might keep {@link CallbackFilter} objects alive to enable caching of
 * generated classes. Prefer using {@code static} classes for implementation of
 * {@link CallbackFilter}.
 * </p>
 */
@FunctionalInterface
public interface CallbackFilter {

  /**
   * Map a method to a callback.
   *
   * @param method
   *         the intercepted method
   *
   * @return the index into the array of callbacks (as specified by
   * {@link Enhancer#setCallbacks}) to use for the method,
   */
  int accept(Method method);

  /**
   * The <code>CallbackFilter</code> in use affects which cached class the
   * <code>Enhancer</code> will use, so this is a reminder that you should
   * correctly implement <code>equals</code> and <code>hashCode</code> for custom
   * <code>CallbackFilter</code> implementations in order to improve performance.
   */
  boolean equals(Object o);
}
